Fire escape devices of the type relating to the present invention are well known in the patent art. Similar devices are known in which a cable is wound on a drum or reel. A variety of mechanisms have been suggested as means to retard the rotational movement of the drum so as to control the rate of cable unwinding and thus determine the speed of descent of an individual suspended from the cable.
One of the typical techniques used to control the rate of descent of the person being lowered by the device includes the use of fluid, or hydraulic friction producing systems. However, most of these prior art devices have suffered from a variety of disadvantages. These include complex piston and cylinder arrangements to pneumatically control the rotational movement of the reel or drum. Such devices require operating fluids of a particular viscosity in order to perform properly and have therefore been found to be impractical particularly for use from excessive heights because of requirements for reservoir capacities. Additionally, prior art devices appear to suffer from a common disadvantage relating to the ability to control at a relatively constant rate of descent the speed at which human beings of vastly different weights can be lowered from elevated positions. Also, many of the prior art devices are either not reusable or cannot be made portable.
Although the patent literature contains many examples of structures and devices for portable fire escapes, none appear to have become acceptable for wide spread use. Yet, the continued occurences of tragic fires in hi-rise structures, accompanied by the needless loss of life, highlights the need for an effective and usable fire escape device which can be made portable and therefor used both by permanent residents and travellers in hi-rise apartment buildings, office buildings, or hotels as a safe and reliable means of being lowered from a burning structure.